Modeling and assessing natural cross ventilation in buildings

This study investigates the impact of wind direction, building height and room level, building orientation, window orientation, window wall and internal partition on natural ventilation performance. Scenario testing was conducted through the use of Computational Fluid Dynamics (CFD) which were solved numerically using ANSYS-CFX. The Normalized Air Change Rate (NACR), streamlines, Normalized Velocity vector (NVvec) field on the breathing plane and Normalized Local Mean Age (NLMA) of air contours on the breathing plane were used as performance indicators. It was found that the NACR value of a specific level increases with building due to the exposure of higher levels to the wind with higher velocity while it remains independent of other levels’ ventilation state. Unlike window orientation, Wind direction also significantly impacted natural ventilation performance. The ventilation performance was better when windows were directly exposed to the wind direction. The study also highlights the importance of window wall configuration in natural ventilation performance and suggests increasing the fresh air sweeping path from the inlet to the outlet to improve ventilation. Future studies may investigate the effect of large openings and deliberate vertical deviation of entry jet flow for better ventilation performance. This thesis includes 6 chapters in the following order 1- Introduction, 2- Natural Ventilation, 3- Literature Review, 4- Numerical Simulation, 5- Results and Discussion, 6- Conclusions.